Mill for fibrous substances



Jan. 17, 1956 w. RElsTEN MILL FOR FIBROUS SUBSTANCES 2 Sheets-Sheet l Filed Dec. 12, 1951 FAL Jan. 17, 1956 w. REISTEN MILL FOR FIBROUS SUBSTANCES Filed Dec. l2, 1951 2 Sheets-Sheet 2 ATFaQA/Gf United dStates Patent O FOR FIBROUS SUBSTANCES Werner Reisten, Aschaffenburg (Main), Germany Application December 12, 1951, Serial No. 261,317 Claims priority, application Germany December 31, 1948 4 Claims. (Cl. 92-26) This invention relates to a mill for iibrous substances such as paper pulp, cellulose, wood bre pulp, and the like having several pairs of grinding discs, through which the pulp ilows successively. This invention aims at making it possible for the current of pulp to pass through several times, with continuous operation of the mill. in.

With the mill according to the present invention, this is achieved substantially by the fact that the outlet for the pulp is in communication with the inlet for the pulp of the mill in such a manner that the main mass of the pulp flows through the pair of grinding discs in a repeated cycle and a part stream `of the pulp which corresponds to the quantity of pulp introduced continuously into the mill is constantly` discharged from the pulp outlet.

ln order to be able to treat a paste or mass of material of high density, a conveying mechanism, such as a conveyor worm, is disposed, in a preferred embodiment of the invention, in the chamber or pipe connecting the pulp inlet with the pulp outlet. For the same reason, it is expedient to dispose behind the pairs of grinding discs a blade wheel in the pulp outlet, said outlet being preferably formed by a spiral housing containing the blade wheel.

Continuous grinding mechanisms have hitherto been principally used in the paper industry and similar trades only for the after-grinding of material which has had a first grinding in the pulping engine. The high degrees of grinding required for many kinds of substance cannot be obtained by such continuously working mills. The employment of such mills instead of the pulping engine is also a failure because the treatment of masses of material of high density is not possible inthe continually working pulp mills known hitherto.

in contrast, the mill for iibrous material constructed in accordance with the present invention permits the material lto be processed to any degree of grinding occurring in practice with the use of only one machine, because in this machine the main mass of the substance performs a multiple passage through a plurality of pairs of grinding discs. Consequently, substances to be ground to the highest degree of grinding, e. g., for the manufacture of parchment substitute or imitation parchment, can be completely ground in one operation and continuously. More over, the substances can be processed with a maximum density which can be considered for the grinding, so that any character of the products can be achieved. The machine constructed in accordance with the invention surpasses the known pulping engines in grinding output and works with smaller energy requirements. It also oiers considerable operational advantages, due to the absence of interruptions for lling and emptying.

A mill for fibrous material is shown as an'embodiment of the invention in the accompanying drawings, in which- Fig. 1 shows the mill in a horizontal section located at the height of the grinding shaft.

Fig. 2 is a vertical cross-section on line II-II in Fig. l.

Fig. 3 is a vertical cross-section on line III-III in Fig. l.

Fig. 4 is a developed circular section through a pair of grinding discs on line IV-IV in Fig. 2, and

Fig. 5 is a vertical cross-section on line V-*V in Fig. 1.

The main housing of the mill is composed of a plurality of cylindrical parts 1, 2, 3 and 4, which are irmly and tightly connected with each other. Between these parts, the stationary grinding discs 5, 6 and 7' are mounted on their circumference. The rotating grinding discs 8, 9 and 10 are secured on the shaft 11, which, by means of packing bushings 12 and 13, is carried through the front Wall of the housing part 4 and through the housing cover 14 and rotatably mounted in the bearings 15 and 16.

The shaft 11 carries in addition the blade wheel 17, which rotates in the housing part 1, the superficies of which is of spiral shape and merges into the outlet 18 of the mill. On the same side of the machine there is an inlet nozzle 19 on the cylindrical housing part 4.

As a connection between the outlet 18 and the inlet 19 of the mill, a three-part housing 39, 20, 40 is disposed parallel to the shaft 11. In this housing there rotates a conveyor worm 21 mounted in the bearings 26 and 27, said conveyor worm being driven by the shaft 11 at about one third of its speed via the V-belt pulleys 22 and 24 and the V-belt 23. The supply channel 25, shown in Fig. 2, for the fibrous material opens from above into the part 40 of the housing. A pipe 38, through which a part stream leaves the mill, branches off from the initial part 39 of the conveyor worm.

The hydraulic mechanism `for loading and unloading the rotating grinding discs 8, 9 and 10 consists in its principal parts of the cylinder 28 and the piston 29, the rod 3i) of which is connected with the shaft 11 by way of the coupling 31. The cylinder 28 is secured to the housing part 4 of the mill by means of the intermediate member 32. The liquid pressure acting upon the piston 29 can be varied as desired by known means (not shown), and the pressure prevailing between the grinding discs can be measured directly by the height of the liquid pressure.

As can be seen from Figs. 2 to 4, the grinding discs are so constructed that the rotating discs 8, 9 and 10 have radial openings 33 and form blades 34 on the inilow side. T he grinding mechanism segments 35 are secured on the disc between the openings 33 on the side facing the fixed grinding discs. The stationary discs 5, 6 and 7 also have radial guide openings 36 and grinding mechanism segments 37 disposed therebetween, which segments 37 may be composed of stone orsteel. The guide openings 33 and 36 have the effect that the material is conducted on the shortest path over the grinding surface in succession and is rapidly ground to high degrees of grinding with comparatively little power consumption.

The modus operandi of the mill for fibrous material is as follows. A stream of material, which passes through the inlet 19 to the pairs of grinding discs, is continuously fed to the mill through the chute 25. On arriving at the discs, it is guided between the grinding mechanism segments through the guide openings 33 of the rotating grinding discs by the blades 34. After the material has left the guide openings 36 of the last stationary grinding discs 5, it is propelled into the initial part 39 ofthe worm housing by the blade wheel 17.

The largest part of the material is gripped by the worm 21 and again conveyed to the inlet 19 of the mill, whilst a part stream leaves the mill through the pipe nozzle 33. The quantity of material conveyed by the worm remains constant, so that at any time only as much material is discharged through the pipe 38 as is supplied to the mill through the pipe 25. For example, the amount of completely ground material emerging from the mill can znaqpm skilled in the art after understanding the invention, thatV various changes and modifications may be made Without departing from the spirit and scopeof the invention, and it is intended, therefore, to cover all such changes and modifications in the appended claims.

What is claimed as new and desired to be secured by Letters Patent is:

l. A mill for the continuous grinding of fibrous material such as paper pulp, cellulose or wood libre pulp, comprising a` plurality of pairs of discs provided with radial openings, each pair consisting of a stationary and a rotary disc through one after the other of which the pulp can flow in a substantially axial direction from the inlet end portion to the outlet end portion of said mill, said mill being provided with an inlet port for the admission of fresh pulp and an outlet port in said portions, respectively, a conduit directly connecting said outlet end por tion to said inlet end portion, said conduit having its entrance intermediate said discs and said outlet port,` and a power driven conveying means interiorly of said conduit to cause a larger fraction of the quantities of pulp having passed through said discs to ow from said outlet end portion to said inlet end portion.

2. A mill as claimed in claim l, wherein each disc includes grinding segments facing the grinding segments of the coordinate disc, and being provided with radial openings intermediate said segments, each radial opening of a rotary disc being substantially nozzle-shaped in cross section and wider on the face of said disc remote from the coordinate stationary disc than on its other i `ace,andy the one flank of each opening forming with the other flank of the adjacent opening of said rotary disc a sharpredge projecting in the direction of rotation.

3. A mill as claimed in claim l, in which said outlet end portion of said mill is spiral shaped in a plane at right angles to the axis of said discs further comprising ay blade Wheel in said outlet end portion, said wheel being coaxial and rotatable with said rotary discs.

4. A mill as claimed in claim l, said conduit being parallel to the axis of rotation ofrsaid discs, and said conveying means being a worm rotated in. conjunction with said rotary discs.

References Cited in the file of this patent UNITED STATES PATENTS 310,940 Gould Jan. 20, 1885 807,228 Y Wurster Dec. 12, 1905 848,484 Newnham Mar. 26, 1.907 1,173,750 Shartle Feb. 29, 1916 1,187,932 Ryther .lune 20, 1916- y 1,553,976 Bernot et al Sept. l5, 1-925 1,917,505 DeCew July 11, 1933 1,970,330 Mason Aug. 14, 1934 2,164,040 Offermanns June 27, 1939 2,460,278 Cook Feb; 1,V 1949 FOREIGN PATENTS 4,306 Great Britain 1909 82,530 Sweden Feb. 5, 1935 

1. A MILL FOR THE CONTINUOUS GRINGING OF FIBROUS MATERIAL SUCH AS PAPER PULP, CELLULOSE OR WOOD FIBRE PULP, COMPRISING A PLURALITY OF PAIRS OF DISCS PROVIDED WITH RADIAL OPENINGS, EACH PAIR CONSISTING OF A STATIONARY AND A ROTARY DISC THROUGH ONE AFTER THE OTHER OF WHICH THE PULP CAN FLOW IN SUBSTANTIALLY AXIAL DIRECTION FROM THE INLET END PORTION TO THE OUTLET END PORTION OF SAID MILL, SAID MILL BEING PROVIDED WITH AN INLET PORT FOR THE ADMISSION OF FRESH PULP AND AN OUTLET PORT FOR THE ADMISSION TIVELY, A CONDUIT DIRECTLY CONNECTING SAID OUTLET END PORTION TO SAID INLET END PORTION, SAID CONDUIT HAVING ITS ENTRANCE INTERMEDIATE SAID DISC AND SAID OUTLET PORT, AND A POWER DRIVEN CONVEYING MEANS INTERIORLY OF SAID CONDUIT TO CAUSE A LARGER FRACTION OF THE QUANTITIES OF PULP HAVING PASSED THROUGH SAID DISC TO FLOW FROM SAID OUTLET END PORTION TO SAID INLET END PORTION. 